Re: "Non-standard UI"

[Dmitry Gutov]

On 08.03.2020 2:53, Juri Linkov wrote:
> > > rgrep/vc-git-grep provides good UI.
> >
> > No, it doesn't. It's the bare-bone-est UI possible, and it wastes a lot of
> > horizontal space. It doesn't provide a means to search-and-replace. And
> > it's not fit for programmatic construction, so Xref can't use it.
>
> If you don't like the grep output format, you can replace 'grep-filter'
> with your own process filter that would transform it to any other format.

Or I can reuse the existing code.

The suggestion is not bad, but the grep-filter approach isn't going to 
work for Xref, at least, because the data format is a list of values.

And there's not much point in writing code to re-create Xref's UI in yet 
another way, if it can't replace the existing builder.

Overall, grep itself is fast, and we've done enough optimization on the 
way its results are processed that it being synchronous shouldn't be a 
significant problem on modern systems with small-to-medium projects, at 
least. But, of course, we could do better.

> We already had 2 different formats: grep and occur, and now came a new
> 3rd format: xref.  I think any attempt to standardize on the output format
> should be welcome.

Of course. But that would take some concerted effort, and not a 
dismissive attitude.

All three have some valuable features (Occur's inline editing feature 
comes to mind), but they also have each own domain of application thus 
far. So it would require work to make the features work everywhere (e.g. 
have Occur's inline editing work without visiting all files in advance).

> Of course, a general UI should be customizable enough
> to provide look and feel of any of the current formats.

So far, Xref provides variables xref-show-xrefs-function and 
xref-show-definitions-function, and I know for a fact that there are 
third-party packages out there that take advantage of these variables.

> Why not take the best parts from these contenders?
> Take async part of finding matches from grep and
> transform its output to any format you like.

I surely wouldn't refuse an extension of Xref API to asynchronous 
fetching of results. It's unlikely to work though grep-filter, though.